code review 6428053: sync: mention that WaitGroup.Add panics

sync: mention that WaitGroup.Add panics
Fixes issue 3839.

[r, 2012-07-19 18:47:22]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go

[bradfitz, 2012-07-19 18:52:20]

LGTM
 On Jul 19, 2012 11:47 AM, <r@golang.org> wrote:

> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go
>
>
> Description:
> sync: mention that WaitGroup.Add panics
> Fixes issue 3839.
>
> Please review this at
http://codereview.appspot.com/**6428053/<http://codereview.appspot.com/6428053/>
>
> Affected files:
>   M src/pkg/sync/waitgroup.go
>   M src/pkg/sync/waitgroup_test.go
>
>
> Index: src/pkg/sync/waitgroup.go
> ==============================**==============================**=======
> --- a/src/pkg/sync/waitgroup.go
> +++ b/src/pkg/sync/waitgroup.go
> @@ -32,10 +32,11 @@
>
>  // Add adds delta, which may be negative, to the WaitGroup counter.
>  // If the counter becomes zero, all goroutines blocked on Wait() are
> released.
> +// If the counter goes negative, Add panics.
>  func (wg *WaitGroup) Add(delta int) {
>         v := atomic.AddInt32(&wg.counter, int32(delta))
>         if v < 0 {
> -               panic("sync: negative WaitGroup count")
> +               panic("sync: negative WaitGroup counter")
>         }
>         if v > 0 || atomic.LoadInt32(&wg.waiters) == 0 {
>                 return
> Index: src/pkg/sync/waitgroup_test.go
> ==============================**==============================**=======
> --- a/src/pkg/sync/waitgroup_test.**go
> +++ b/src/pkg/sync/waitgroup_test.**go
> @@ -50,7 +50,7 @@
>  func TestWaitGroupMisuse(t *testing.T) {
>         defer func() {
>                 err := recover()
> -               if err != "sync: negative WaitGroup count" {
> +               if err != "sync: negative WaitGroup counter" {
>                         t.Fatalf("Unexpected panic: %#v", err)
>                 }
>         }()
>
>
>

[r, 2012-07-19 18:55:10]

*** Submitted as http://code.google.com/p/go/source/detail?r=05f9fa32500a ***

sync: mention that WaitGroup.Add panics
Fixes issue 3839.

R=golang-dev, bradfitz
CC=golang-dev
http://codereview.appspot.com/6428053